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4 authors
  1. Sep 17, 2013
    • Ralf Baechle's avatar
      MIPS: Fix accessing to per-cpu data when flushing the cache · ff522058
      Ralf Baechle authored 
      
This fixes the following issue

BUG: using smp_processor_id() in preemptible [00000000] code: kjournald/1761
caller is blast_dcache32+0x30/0x254
Call Trace:
[<8047f02c>] dump_stack+0x8/0x34
[<802e7e40>] debug_smp_processor_id+0xe0/0xf0
[<80114d94>] blast_dcache32+0x30/0x254
[<80118484>] r4k_dma_cache_wback_inv+0x200/0x288
[<80110ff0>] mips_dma_map_sg+0x108/0x180
[<80355098>] ide_dma_prepare+0xf0/0x1b8
[<8034eaa4>] do_rw_taskfile+0x1e8/0x33c
[<8035951c>] ide_do_rw_disk+0x298/0x3e4
[<8034a3c4>] do_ide_request+0x2e0/0x704
[<802bb0dc>] __blk_run_queue+0x44/0x64
[<802be000>] queue_unplugged.isra.36+0x1c/0x54
[<802beb94>] blk_flush_plug_list+0x18c/0x24c
[<802bec6c>] blk_finish_plug+0x18/0x48
[<8026554c>] journal_commit_transaction+0x3b8/0x151c
[<80269648>] kjournald+0xec/0x238
[<8014ac00>] kthread+0xb8/0xc0
[<8010268c>] ret_from_kernel_thread+0x14/0x1c

Caches in most systems are identical - but not always, so we can't avoid
the use of smp_call_function() by just looking at the boot CPU's data,
have to fiddle with preemption instead.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5835
      ff522058
  3. Jul 15, 2013
    • Paul Gortmaker's avatar
      MIPS: Delete __cpuinit/__CPUINIT usage from MIPS code · 078a55fc
      Paul Gortmaker authored 
      commit 3747069b25e419f6b51395f48127e9812abc3596 upstream.

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit  -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings.  In any case, they are temporary and harmless.

Here, we remove all the MIPS __cpuinit from C code and __CPUINIT
from asm files.  MIPS is interesting in this respect, because there
are also uasm users hiding behind their own renamed versions of the
__cpuinit macros.

[1] https://lkml.org/lkml/2013/5/20/589



[ralf@linux-mips.org: Folded in Paul's followup fix.]

Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5494/
Patchwork: https://patchwork.linux-mips.org/patch/5495/
Patchwork: https://patchwork.linux-mips.org/patch/5509/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      078a55fc
  5. May 08, 2013
  7. May 01, 2013
  9. Apr 05, 2013
  11. Feb 17, 2013
  13. Feb 01, 2013
  15. Dec 13, 2012
  17. Nov 09, 2012
  19. Sep 13, 2012
  21. Jul 19, 2012
  23. Jul 06, 2012
  25. May 16, 2012
  27. Mar 28, 2012
  29. Mar 20, 2012
  31. Dec 07, 2011
  33. Oct 20, 2011
  35. Jul 25, 2011
    • Kevin Cernekee's avatar
      MIPS: Add SYNC after cacheflush · d0023c4a
      Kevin Cernekee authored 
      
On processors with deep write buffers, it is likely that many cycles
will pass between a CACHE instruction and the time the data actually
gets written out to DRAM.  Add a SYNC instruction to ensure that the
buffers get emptied before the flush functions return.

Actual problem seen in the wild:

1) dma_alloc_coherent() allocates cached memory

2) memset() is called to clear the new pages

3) dma_cache_wback_inv() is called to flush the zero data out to memory

4) dma_alloc_coherent() returns an uncached (kseg1) pointer to the
freshly allocated pages

5) Caller writes data through the kseg1 pointer

6) Buffered writeback data finally gets flushed out to DRAM

7) Part of caller's data is inexplicably zeroed out

This patch adds SYNC between steps 3 and 4, which fixed the problem.

Signed-off-by: default avatarKevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: 
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      d0023c4a
  37. May 19, 2011
  39. May 10, 2011
    • Ralf Baechle's avatar
      MIPS: c-r4k: Fix GCC 4.6.0 build error · 71271aab
      Ralf Baechle authored 
      
  CC      arch/mips/mm/c-r4k.o
arch/mips/mm/c-r4k.c: In function 'probe_scache':
arch/mips/mm/c-r4k.c:1078:6: error: variable 'tmp' set but not used [-Werror=unused-but-set-variable]
cc1: all warnings being treated as errors

Older GCC versions didn't warn about the unused variable tmp because it was
getting initialized.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      71271aab
  41. Apr 06, 2011
  43. Oct 29, 2010
  45. Jun 24, 2009
  47. Jun 17, 2009
  49. May 14, 2009
  51. Mar 30, 2009
    • Manuel Lauss's avatar
      MIPS: Alchemy: unify CPU model constants. · 270717a8
      Manuel Lauss authored 
      
This patch removes the various CPU_AU1??? model constants in favor of
a single CPU_ALCHEMY one.

All currently existing Alchemy models are identical in terms of cpu
core and cache size/organization.  The parts of the mips kernel which
need to know the exact CPU revision extract it from the c0_prid register
already; and finally nothing else in-tree depends on those any more.

Should a new variant with slightly different "company options" and/or
"processor revision" bits in c0_prid appear, it will be supported
immediately (minus an exact model string in cpuinfo).

Signed-off-by: default avatarManuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      270717a8
  53. Mar 23, 2009
  55. Jan 30, 2009
  57. Sep 05, 2008
  59. Jun 26, 2008
  61. Jun 16, 2008
  63. Apr 28, 2008
  65. Apr 07, 2008
  67. Mar 12, 2008
  69. Feb 19, 2008
    • Ralf Baechle's avatar
      [MIPS] Handle I-cache coherency in flush_cache_range() · 2eaa7ec2
      Ralf Baechle authored 
      
So far flush_cache_range() did't consider the I-cache largely because it
did rarely ever matter to real world code.  This was working primarily
because normally code and data are don't share the same pages - with the
exception of MIPS16 code which uses address constants embedded between
the code.   The following sequence of events may break the code:

 o MIPS16 executable being loaded
 o dynamic linker relocates the address constants embedded into the code:
 o   Uses mprotect(2) to make code pages PROT_READ|PROT_WRITE
 o   Performs the actual relocations by writing to the pages which likely
     are COW.  Because no PROT_EXEC is set I-cache coherence will not be
     considered.
 o   Uses mprotect(2) to switch code pages back to PROT_READ|PROT_EXEC.
     This results in a call to flush_cache_range() which also does not
     consider I-caches.
 o => executing the page just having been relocated may now result in the
   I-cache getting refilled with stale data from memory.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      2eaa7ec2
  71. Feb 03, 2008